Thursday, June 21, 2007

Drivetrain & Chain Wear


Over the last few weeks I noticed that in certain gears my chain sort of skips. This is the only way I can explain it. It's not slipping to another gear although it sort of sounds like it. There were no problems with the shifting or the derailleurs either. Well the problem has been getting steadily worse and it happens in all my favorite gears. Thus we now enter a place that I really knew nothing about - Drivetrain wear.

I know the importance of keeping your chain properly clean and lubed. I knew that chains 'stretch' and will eventually wear out. What I did not know is that the chain rings and rear cassette wear out. Seems pretty obvious eh? Metal parts, constantly being used, they gotta wear sometime. I started to look into what the problem could be and came across a great article on Sheldon Browns website - http://sheldonbrown.com/chains.html and the sub article, with some great photos examples - http://sheldonbrown.com/chains.html#wear. In a nutshell, all the little teeth on the cogs start out with nice even little valleys and flat tops, sort of like a castle embattlement. After a while of the chain wearing on the teeth, the nice little valleys become little slopes and as the chain is wearing and 'stretching' at the same time it will start to ride up higher on the teeth. And you end up with problems like I was having.

So with my new found knowledge of what might be the problem I rode down to the local bike shop and had them look at it.
Bike mechanic - "What's the problem? (or) What are we looking at? (or something like that.)
Me - Well, I think my drivetrain may be going.
Bike mechanic - then grabbed a few links of the chain, squeezed and pulled on them, and said,"Yep your drivetrain is shot. You let it go to long."
As he did this even I could easily see the play between the links and tell that inside each one of those pins had a little worn spots on them. As a result the worn chain had done more damage to the cogs. He told me that I should come in once a month and have them check my chain. If the chain is replaced in time the rest of the drivetrain will last longer. I asked how long drivetrains normally do last and he told me somewhere between 500 - 1500 miles but he's seen them last much longer. I've had mine for 4500 miles now so I guess I got some good use out of it. We replaced the middle chain ring, the rear cassette and the chain, which with labor cost me about $136.00 and took about 20 minutes. I've put about 2600 miles on my bike since last June so it looks like I could be doing this sort of thing once a year.

Odo - 4459.1

Monday, June 11, 2007

Field Fix - Cut Tire

I found this on the REI website.

Expert Advice Imageour tire's blown, your handlebar busted, your chain broken. But if you think you're in for a long walk home, think again. There are fixes to almost any problem you can encounter in the field.

The Problem: Your tire is cut and the tube is trying to sneak through.

The Solution: Welcome to the strange science of booting. Take a power bar wrapper, a dollar bill (they're made of cotton and linen, not paper), the baggy that was holding your sandwich or any other similarly strong substance that can withstand some wetness and wear and tear.

Place the boot material inside the tire over the cut (after making sure that any sharp objects that may have caused the cut are removed).

Then, pump up your tube and ride away. But be sure to replace your tire as soon as possible.

Bonus Repairs



The Problem: Your tube is blown and your patch kit seems to have left town.

The Solution: Mole Skin can be used to patch a tire casing. It has an adhesive backing to keep it in place until you can replace the tire. Mole Skin can hold tire pressures up to 65 PSI. Posted by Larry.

The Problem: Your tube is blown and your pump bit it on that last drop-off.

The Solution: Believe it or not, you can pack your tire with leaves, straw, or grass and limp home that way. Posted by Tim.

Tuesday, June 05, 2007

Ahhh! My knee is feeling pretty good now. I got a new record time riding to work Saturday.

Distance - 5.8 miles
Average speed - 16.5 mph
Maximum speed - 31.0 mph
Time - 21:00

17 seconds off from my last time. Last time I had a killer tailwind pushing me. This time I was fighting a slight headwind. This was also at about 4:30 in the morning with no traffic.

Odo - 4315.9

Sunday, June 03, 2007

May's Critical Mass

Last Critical Mass had a great turnout. I was having a good time until my chain slipped off my highest gear and got stuck between the gear and the frame. I had to take the back wheel off to get it out. By that time everyone was gone. I rode around downtown a little while hoping I would see them to no avail. It's amazing how fast that many people on bikes can disappear. Especially when their hooting, hollering and beating on drums. Yeah their are some bicycle drummers in there now. Anyway I took a few pictures this time.